Control of metastases in the Nb rat prostatic adenocarcinoma model

Carprofen induction of p75NTR-dependent apoptosis via the p38 mitogen-activated protein kinase pathway in prostate cancer cells

The p75 neurotrophin receptor (p75(NTR)) functions as a tumor suppressor in prostate epithelial cells, where its expression declines with progression to malignant cancer. Previously, we showed that treatment with R-flurbiprofen or ibuprofen induced p75(NTR) expression in several prostate cancer cell lines leading to p75(NTR)-mediated decreased survival. Using the 2-phenyl propionic acid moiety of these profens as a pharmacophore, we screened an in silico database of 30 million compounds and identified carprofen as having an order of magnitude greater activity for induction of p75(NTR) levels and inhibition of cell survival. Prostate (PC-3 and DU-145) and bladder (T24) cancer cells were more sensitive to carprofen induction of p75(NTR)-associated loss of survival than breast (MCF-7) and fibroblast (3T3) cells. Transfection of prostate cell lines with a dominant-negative form of p75(NTR) before carprofen treatment partially rescued cell survival, showing a cause-and-effect relationship between carprofen induction of p75(NTR) levels and inhibition of survival. Carprofen induced apoptotic nuclear fragmentation in prostate but not in MCF-7 and 3T3 cells. Furthermore, small interfering RNA knockdown of the p38 mitogen-activated protein kinase (MAPK) protein prevented induction of p75(NTR) by carprofen in both prostate cell lines. Carprofen treatment induced phosphorylation of p38 MAPK as early as within 1 min. Expression of a dominant-negative form of MK2, the kinase downstream of p38 MAPK frequently associated with signaling cascades leading to apoptosis, prevented carprofen induction of the p75(NTR) protein. Collectively, we identify carprofen as a highly potent profen capable of inducing p75(NTR)-dependent apoptosis via the p38 MAPK pathway in prostate cancer cells.

COX-2 inhibitors and other nonsteroidal anti-inflammatory drugs in genitourinary cancer

Selective cyclooxygenase (COX)-2-inhibiting and other nonsteroidal anti-inflammatory drugs (NSAIDs) show promise for preventing and treating bladder and prostate cancers. In contrast to the strong NSAID epidemiology in colorectal cancer, the epidemiologic data on NSAIDs and genitourinary (GU) cancers are limited and mixed. However, a substantial body of preclinical in vitro and in vivo animal model data shows consistent NSAID activity in treating, and in some cases preventing, GU cancers and begins to address the mechanisms behind this activity (eg, involving Akt and ERK2 in the prostate). Many preclinical and clinical NSAID studies currently under way are helping to resolve the best type (selective or nonselective COX inhibitors or non-COX inhibitors), dose and duration of NSAID treatment for prevention in the GU setting. Future studies likely will focus on clarifying the NSAID mechanisms behind and developing NSAID combinations for both treating and preventing GU cancers.

Case-control study of use of nonsteroidal antiinflammatory drugs and glioblastoma multiforme

Evidence from epidemiologic and experimental studies suggests that use of nonsteroidal antiinflammatory drugs (NSAIDs) reduces risk of colon and breast cancer. The association between use of aspirin and other NSAIDs and risk of adult glioblastoma multiforme (GBM) was evaluated among 236 incident GBM cases and 401 population-based controls frequency-matched on age, gender, and ethnicity from the San Francisco Bay Area Adult Glioma Study. Cases (or proxies) and controls were interviewed in person between May 1997 and August 2000. Cases with self-reported GBM reported less use of at least 600 pills of all types of NSAIDs combined during the 10-year prediagnostic period than did controls (odds ratio (OR) = 0.53, 95% confidence interval (CI): 0.3, 0.8). Findings were consistent for aspirin (OR = 0.51, 95% CI: 0.3, 0.8), ibuprofen (OR = 0.41, 95% CI: 0.2, 0.8), and naproxen/other NSAIDs (OR = 0.34, 95% CI: 0.1, 0.8). GBM cases also reported less use of acetaminophen than did controls (OR = 0.51, 95% CI: 0.3, 1.0). Eliminating participants who initiated NSAID use within 2 years of diagnosis yielded similar results. These findings show an inverse association between NSAID use and GBM. Further studies are warranted to determine whether NSAIDs might be effective in the inhibition of GBM development or progression.

Aspirin and epithelial ovarian cancer

BACKGROUND

Epidemiological evidence suggests that chronic inflammation may influence ovarian carcinogenesis. The study objective was to examine the association between the commonly used anti-inflammatory drug aspirin and epithelial ovarian cancer.

METHODS

The authors conducted a case-control study based in the New York University Women's Health Study cohort enrolled between 1985 and 1991 in New York City. After a median follow-up period of 12 years, 68 incident cases of epithelial ovarian cancer were identified. Data about regular aspirin use were collected during the 1994-1996 follow-up questionnaire. Using a case-control study design, 10 controls per case were randomly selected among study participants who matched the case by age and menopausal status. Conditional logistic regression analysis was used to study the relationships between aspirin and epithelial ovarian cancer by generating odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Relative to no aspirin use, the OR for epithelial ovarian cancer among women who reported aspirin use three or more times per week for a period of at least 6 months was 0.60 (95% CI 0.26, 1.38), after adjustment for age at menarche, parity, oral contraceptive use, and first-degree family history of breast cancer before age 50. Among recent, within the previous 5 years, users of aspirin, the adjusted OR was 0.36 (95% CI 0.11, 1.18).

CONCLUSION

Although confidence intervals included unity, the observed risk estimates seem to be compatible with previous studies suggesting that regular aspirin use could be inversely associated with risk of epithelial ovarian cancer.

Contrasting effects of aspirin on prostate cancer cells: suppression of proliferation and induction of drug resistance

BACKGROUND

Aspirin is widely used as a preventive measure against occlusive vascular diseases. Since the age group in which aspirin use has become prevalent is similar to the one presenting with prostate cancer, we decided to examine the potential effects of aspirin on prostate cancer.

METHODS

We studied the effects of plasma-attainable concentrations of aspirin (0.5-2 mM) on the human prostate cancer cell lines LNCaP, PC-3, and DU 145, employing cytotoxicity assays and flow cytometric analyses.

RESULTS

Incubation with aspirin for 3 days reduced cellular proliferation by up to 35-55% in each cell line studied, but induced a tripling of the percentage of cells expressing P-glycoprotein (an efflux pump conferring multidrug resistance) only in the LNCaP cells. Both effects were dose-dependent. The effect on P-glycoprotein expression was reflected in the induction of resistance against adriamycin cytotoxicity. Furthermore, this protective effect of aspirin was reversed by a specific P-glycoprotein inhibitor, PSC833. The cellular expression of P-glycoprotein returned to normal within 3 days following the removal of aspirin. Aspirin did not affect the cell cycle distribution of LNCaP cells.

CONCLUSIONS

This study suggests that aspirin enhances the ability of androgen-responsive prostate cancer cells to resist chemotherapeutic drugs. These findings could potentially have significant clinical ramifications for prostate cancer patients taking aspirin shortly before or during chemotherapeutic sessions.

Long term tumorigenicity of a single application of indomethacin or Amuno in adolescent and in adult male Sprague Dawley rats

200 adolescent (Group I) and 200 adult male Sprague Dawley rats (Group II) were divided into 4 subgroups of 50 animals each. Animals were treated on the 29th (Group I) or 98th day of life (Group II) either with acetone or Amuno carrier in acetone or Amuno on acetone (2.5 mg indomethacin/100 g animal weight in acetone) or with the pure substance indomethacin 2.5 mg/100 g of animal weight in acetone, giving a single application on the shaved dorsal skin. Subsequently the animals remained under observation until their deaths, followed by autopsy and histopathologic examination of several organs. The rats treated with Amuno of indomethacin in the adolescent stage showed lower body weights and a shorter total survival time. The adolescent animals treated with Amuno or indomethacin showed a significantly higher rate of interstitial testicular tumors of the Leydig tumor type, adenomas and adenocarcinomas of the small and large intestine as well as hepatocellular tumors. The total number of neoplasias was higher in the animals treated with Amuno or indomethacin compared to those treated with acetone or carrier with acetone. Application of Amuno or indomethacin also resulted in a higher rate of hyperplasias (sole of foot, lymph nodes, prostate). The impairment of the synthesis of prostaglandins caused by indomethacin apparently results in starting complex pathomechanisms which have effects until the late death of the animals. Adolescent animals were affected more frequently by the application of indomethacin as were already adult animals.

Metastasis in the androgen-insensitive Nb rat prostatic carcinoma system

This unit has in the past evaluated the Nb rat prostatic adenocarcinoma model with respect to chemotherapies. Recently, this unit has been evaluating agents that may have a role in decreasing metastatic rate. The three androgen-insensitive tumors, Nb Pr A.I. I, II, III, have been evaluated herein. Agents that have been used include indomethacin, heparin, heparin plus cortisone, and heparan sulfate (SP54). It has been shown that these agents do play a role in reducing the metastasis. In evaluation of Nb Pr A.I, I, control animals had a metastatic rate of 57%. In treatment with indocin, only 21% of the animals, three of 14 animals treated, had a metastasis, and treatment with heparin and cortisone resulted in one of 14 animals having metastasis. Similar observations were seen when treatment with SP54 and heparin was evaluated in the Nb Pr A.I. III; 18 and 27% of treatment group animals had metastasis, whereas 55% of control groups had metastasis. Similarly, in the Nb Pr A.I. II evaluation, control animals having a metastatic rate of 43% had heparin plus cortisone and heparin alone, and this particular tumor model revealed complete resolution with no animals having metastatic disease. The majority of these agents have not effected tumor volume in terms of reduction as much as the best chemotherapeutic agents in this model system include cyclophosphamide and cis-platinum.